COMBINED DEVICES WITH DUAL PURPOSE: GAS DETECTORS THAT WARN ABOUT THE PRESENCE OF FIRE AND MEASURE INDOOR GAS POLLUTION

The article discusses certification methods of combined devices with dual purpose: gas detectors that warn about the presence of fire and measure indoor gas pollution. Requirements in the current regulatory documents (European standards) for the design and testing methods of such devices are examined. It is demonstrated that the current standards concerning fire gas detectors and gas detectors of CO do not contain essentially contradictory requirements and can be unified and applied to the combined dual-purpose devices that are described in this article. With regard to difference in norms of maximum permissible concentrations of CO in Russia and abroad, the concentration of the signal for our CO gas detectors typically corresponds to 50 ppm, which is the same (subject to error) with the signal fire detectors gas concentration. According to EU norms the establishment three thresholds, depending on both the concentration and the time is required. To demonstrate the feasibility of the three threshold CO alarm that meets the requirements EN 50291, the article describes a signal processing algorithm gas detector carbon monoxide using sensor TGS2442.